pick: remove transaction on the whole command (issue6037) At its core, pick is a pretty straightforward and well-behaving command, it uses functions already in core hg, it checks that wdir is clean and that changeset to pick is not public, it checks if there happen to be merge conflicts and can be --continue'd later, etc. It is very similar to graft in core (it also uses mergemod.graft function), but it obsoletes the original changeset. However, graft does not experience this incorrect behavior from issue 6037. What happens in the test case for this issue when we pick a revision that touches both "a" and "b": mergemod.graft() takes the original changeset and tries to apply it to the wdir, which results in "b" being marked as newly added and ready to be committed, "a" updated with the new content and being marked as modified, but "a" also has conflicts. Pick correctly notices this and saves its state before asking for user intervention. So far so good. However, when the command raises InterventionRequired to print a user-facing message and exit while being wrapped in repo.transaction() context manager, the latter partially undoes what mergemod.graft() did: it unmarks "b" as added. And when user continues pick, "b" is therefore not tracked and is not included in the resulting commit. The transaction is not useful here, because it doesn't touch wdir (it's still dirty), it doesn't remove pickstate (and other commands will refuse to work until pick --abort or --continue), it just makes "b" untracked. The solution is to use repo.transaction() only to wrap code that writes data to hg store in the final stages of the command after all checks have passed and is not expected to fail on trivial cases like merge conflicts. For example, committing the picked changeset. But since pick uses repo.commit() for that, and because that function already uses a transaction, wrapping it in another transaction doesn't make sense.

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.. Copyright 2011 Pierre-Yves David <pierre-yves.david@ens-lyon.org>

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..                Logilab SA        <contact@logilab.fr>

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Good practice for (early) users of evolve

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Avoid unstability

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The less unstability you have the less you need to resolve.

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Evolve is not yet able to detect and solve every situation. And your mind is

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not ready neither.

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Branch as much as possible

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This is not MQ; you are not constrained to linear history.

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Making a branch per independent branch will help you avoid unstability

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and conflict.

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Rewrite your changes only

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There is no descent conflict detection and handling right now.

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Rewriting other people's changesets guarantees that you will get

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conflicts. Communicate with your fellow developers before trying to

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touch other people's work (which is a good practice in any case).

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Using multiple branches will help you to achieve this goal.

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Prefer pushing unstability to touching other people changesets

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If you have children changesets from other people that you don't really care

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about, prefer not altering them to risking a conflict by stabilizing them.

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Do not get too confident

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This is an experimental extension and a complex concept. This is beautiful,

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powerful and robust on paper, but the tool and your mind may not be prepared for

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all situations yet.